1. Field of Invention
The present invention relates to cable reels of reverse type to be installed on a steering apparatus of a vehicle, and to methods of their formation. More particularly, the present invention relates to the improvement of a reverse ring for reversing a flat cable accommodated in an annular hollow space formed by a movable member and a stationary member.
2. Description of Related Art
A cable reel of reverse type to be installed on the steering apparatus of a vehicle, as shown in FIGS. 8A and 8B, has been proposed. In the cable reel of FIGS. 8A and 8B, a stationary member 19 serving as an outer cylinder is fixed to a steering column (not shown), and a movable member 12 serving as an inner cylinder is fixed to a steering wheel (not shown). The stationary member 19 and the movable member 12 are connected so as to be rotatable relative to each other. An annular rotary ring 17 made of synthetic resin is freely rotatably accommodated in the annular hollow space 18 formed by the stationary member 19 and the movable member 12. Reverse rings 15 and 16 made of synthetic resin are locked to the rotary ring 17.
In the annular hollow space 18, flat cables 13 and 14 each having one end connected to the movable member 12 are wound in a space C5 disposed between the movable member 12 and the reverse rings 15 and 16 and pass through two reverse gaps C6 disposed between the reverse rings 15 and 16. Then the flat cables 13 and 14 are wound in the opposite direction in a space C4 disposed between the stationary member 19 and the reverse rings 15 and 16. The other end of each of the flat cables 13 and 14 is connected to the stationary member 19.
In this cable reel, when the steering handle or steering wheel is rotated in one direction, the flat cables 13 and 14 pass through the reverse gaps C6 of the reverse rings 15 and 16 by sliding around the U-shape bends at the ends of the reverse rings 15 and 16. In this way, the flat cables 13 and 14 move to the inner side of the reverse ring and are wound on the peripheral surface of the movable member 12. On the other hand, when the steering handle or steering wheel is rotated in the opposite direction, the rewound flat cables 13 and 14 pass through the reverse gaps C6 while they are moving back around the U-shaped bends. The flat cables 13 and 14 move to the outer side of the reverse rings 15 and 16 and are wound on the inner peripheral surface of the stationary member 19.
In the cable reel described above, the reverse rings 15 and 16 are required to reverse the direction of winding of the flat cables 13 and 14. To prevent vibrations of the reverse rings 15 and 16 in the annular hollow space 18, the reverse rings 15 and 16 are locked to the rotary ring 17. That is, to construct the member for reversing the flat cable, three parts are required. These are the two reverse rings 15 and 16 and one rotary ring 17.
With an increase of the number of flat cables in such a cable reel, it is necessary to increase the number of reverse rings. This leads to an increase in the number of component parts and makes the manufacturing cost high.
The reverse rings 15 and 16 are fixed to the rotary ring 17 and thus they are incapable of moving in directions other than the rotary direction. Further, because the reverse rings 15 and 16 are not flexible, there is no change in the width of the space C4 between the stationary member 18 and each of the reverse rings 15 and 16 and that of the space C5 between the movable member 12 and each of the reverse rings 15 and 16.
Accordingly, with an increase in the number of flat cables which pass through each space C5 and C6 due to the rotation of the movable member 12, the width of each space is set, for example, during manufacture by adding an allowance thereto, i.e. each space is made wider if the cable reel carries a larger number of bundles of flat cables. This has the defect that the flat cables 13 and 14 may move freely or loosely in a wider portion of the passage when they are moved in each passage by the rotation of the movable member 12. As a result, the flat cables 13 and 14 generate vibrations and abnormal sounds.
The present invention seeks to reduce or avoid the above-described problem. Accordingly, it is an object of the present invention to reduce the number of component parts in a cable reel of reverse type. A further object is to reduce or prevent generation of vibrations and/or abnormal sounds when a movable member rotates, by improving members for reversing a flat cable which is accommodated in an annular hollow space of a cable reel of reverse type.
Accordingly, the present invention provides a cable reel that includes:
a stationary member;
a rotatable member located with respect to the stationary member so as to define an annular hollow space between the rotatable and stationary members;
a reverse member accommodated in the annular hollow space, the reverse member including a plurality of reverse portions and an annular member, the reverse member being formed in one piece from; and
a flat cable accommodated in the annular hollow space, the flat cable having respective spaced portions fixed with respect to the stationary member and with respect to the rotatable member and an intermediate portion between the spaced portions which is wound on one of the reverse portions.
The reverse member may be made from a resiliently flexible sheet.
Preferably, the reverse portions are radially expansible loops formed so as to press part of the intermediate portion of the flat cable against the stationary member. Typically, each reverse portion is formed by looping an arm projecting from the annular member. Each arm may have a fixed end, fixed to the annular member, and a free end, the free end being slidably movable with respect to the fixed end. Alternatively, each arm may have a fixed end, fixed to the annular member, and a free end., the free end being engageable with the fixed end in order to retain the loop. In that case, the free end of the arm may be engageable with or lockable to the fixed end of the arm via a slot.
The annular member may be disposed centrally of circumferential arm projections which are bent and looped to form the reverse portions.
Preferably, the arm projections are L-shaped.
Each L-shaped arm projection may include a short transverse portion and a long longitudinal portion, the transverse portion connecting the longitudinal portion to the annular member. The slot may be formed on the longitudinal portion, near the fixed end of the arm.
Preferably, to form one of the reverse portions, the transverse portion is bent perpendicularly to the central annular member and the longitudinal portion is looped to form one of the reverse portions. The part of the flat cable wound on each reverse portion may be sandwiched between the outer surface of each reverse ring and the outer wall of the annular hollow portion and, optionally, between the adjacent reverse rings. Thus, when the flat cable moves with the rotation of the movable member, it can be difficult for the flat cable to move freely. This can assist in the suppression of the generation of vibrations and abnormal sounds.
Typically, the central annular member serves as a rotary ring and is disposed on a bottom surface of the annular hollow space. A gap between an inner peripheral surface of each reverse portion and a peripheral surface of the movable member may be identified as an inner peripheral passage for each flat cable to be fixed with respect to the movable member. A gap between the reverse portions adjacent to each other circumferentially may be identified as a reversing passage for each flat cable. A gap between a peripheral surface of each reverse portion and an inner peripheral surface of the stationary member may be identified as an outer peripheral passage for each flat cable.
In use, the rotary ring rotates with the rotation of each reverse ring because the rotary ring is integral with the reverse rings. Thus the rotary ring holds the position of the reverse rings, thus holding the reverse rings in the annular hollow space, with the reverse rings spaced at equal intervals.
In various exemplary embodiments. the reverse member is freely rotatable within the cable reel. That is, the reverse member is not fixed with respect to the rotary member or fixed member. Rotation of the reverse member typically occurs due to tension in the flat cables during winding of the flat cables into the inner peripheral passage. Rotation of the reverse member in the other direction may occur since the flat cables are preferably rigid enough to be capable of pushing the reverse portions during unwinding of the flat cables from the inner peripheral passage.
When the flat cable is wound tightly, the number of turns of the flat cable usually increases. In that case, it may be necessary to increase the width of the inner peripheral passage to accommodate the flat cable. However, in the case where each reverse portion is flexible, the width of the inner peripheral passage is widened according to the number of turns of the flat cable. In this way, it is possible to ensure smooth operation of tight winding of the flat cable.
The flexible sheet is preferably an insulating plastics material sheet. By using an insulating plastics material sheet, it is possible to manufacture a reverse member light in weight and at a low cost which is capable of securely insulating the flat cables in contact with the reverse ring.
Bending of the insulating plastics material sheet may be facilitated by making a bending portion thin. Preferably, the bending applied to the plastics material sheet is not a fully permanent deformation. However, the bending may leave the plastics material with a partial permanent deformation.
It is preferable to provide four reverse portions in the annular hollow space.
Of course, when four reverse portions are disposed in the annular hollow space, they can be used in any case where, for example, one, two, three or four flat cables are used.
When four reverse portions are disposed in the annular hollow portion, it is preferable that each of the four reverse portions (or rings) contacts the flat cable over a sufficient area to ensure that when the movable member rotates, the flat cable has a stable locus.
The number of the reverse portions is not limited to four but one, two or three reverse rings, or more than four reverse rings, may be used.
In another exemplary embodiment, the present invention provides a cable reel including:
a stationary member;
a rotatable member located with respect to the stationary member so as to define an annular hollow space between the rotatable and stationary members;
a reverse member accommodated in the annular hollow space, the reverse member being formed in one piece from a flexible sheet and including a plurality of reverse portions and an annular member, the annular member being disposed centrally of the reverse portions, each reverse portion being formed by bending and looping an L-shaped arm projection which is disposed at a circumference of said annular member; and
a flat cable accommodated in the annular hollow space, the flat cable having respective spaced portions fixed with respect to the stationary member and with respect to the rotatable member and an intermediate portion between the spaced portions which is wound on one of the reverse portions.
In another aspect, the present invention provides a method of forming a cable reel including the formation of a reverse member, wherein the reverse member has a plurality of reverse portions and a central annular member, the reverse portions being disposed at regular intervals in a circumferential direction around the central annular member, the reverse member being formed in one piece from a flexible sheet, the method including the step of bending and looping arm projections to form the plurality of reverse portions.
In another exemplary embodiment, the sheet is an annular sheet and the reverse portions are projections from a surface of the central annular member, the projections being formed by moulding of the annular sheet.
Preferably, the moulding operation gives reverse portions of a kidney shape. Preferably, the moulding is vacuum moulding. The reverse portions may be radially resiliently flexible.
Again, preferably the sheet is an insulating plastics material sheet.
As mentioned above, the reverse member including a plurality of the reverse portions may be formed in one piece by vacuum moulding of an annular sheet. Thus, the reverse member, which is accommodated in the annular hollow space, may be a single component. In this way, the number of component parts may be reduced.
The number of the flat cable-reversing portions required in the cable reel increases with the number of flat cables. However, since a plurality of reverse portions may be formed from one flexible sheet, it is possible to form the required number of reverse portions as a single reverse member component. Therefore, it is possible to reduce the number of component parts in the cable reel.
The formation of the reverse portions may be completed at the time of vacuum moulding. Assembly of the cable reel may be facilitated since the reverse portions are formed on the reverse member prior to assembly, so that it is only necessary simply to insert the reverse member into the annular hollow portion.
In an exemplary embodiment, the present invention provides a cable reel including:
a stationary member;
a rotatable member located with respect to the stationary member so as to define an annular hollow space between the rotatable and stationary members;
a reverse member accommodated in the annular hollow space, the reverse member being formed by vacuum moulding from an annular sheet to give an annular member with moulded projections from a surface of the annular member, the projections being disposed at regular intervals in a circumferential direction around the annular member, each moulded projection being a reverse portion; and
a flat cable accommodated in the annular hollow space, the flat cable having respective spaced portions fixed with respect to the stationary member and with respect to the rotatable member and an intermediate portion between the spaced portions which is wound on one of the reverse portions.
In a further aspect, the present invention provides a method of forming a cable reel including the formation of a reverse member, wherein the reverse member has a plurality of reverse portions, and an annular member, the reverse portions being disposed in a circumferential direction around said annular member.
The reverse member is formed in one piece by moulding of an annular sheet to give the reverse portions which project from a surface of the annular member.
In another aspect, the present invention provides a vehicle having a steering assembly including a cable reel according to any one of the above aspects.